2006ApJ...651L..45F

We present observations with the INTEGRAL IBIS telescope of the wind nebula powered by the young pulsar B1509-58, and we discuss the spatial and spectral properties of the unpulsed emission in the 20-200 keV energy band. The source extension and orientation along the northwest-southeast axis correspond to the jet emission seen at keV and TeV energies. The hard X-ray spectrum is consistent with the earlier BeppoSAX measurements. It follows a power law with a photon index α=-2.12±0.05 up to 160 keV. A possible break at this energy is found at the 2.9 σ confidence level. The 0.1-100 keV data are consistent with synchrotron aging of pairs in the jet and yield a magnetic field strength of 22-33 µG for a bulk velocity of 0.3c-0.5c. The synchrotron cutoff energy thus corresponds to a maximum electron energy of 400-730 TeV.